(1) Field of the Invention
This invention relates in general to a radiator for internal combustion engines and, in more particular, to a horizontal type radiator in which a bank of flat radiating tubes are horizontally disposed between a pair of opposite header tanks.
(2) Description of the Prior Art
There have been various types of horizontal type radiators developed for internal combustion engines. One representative such radiator, proposed by the inventor of this invention, is illustrated in FIGS. 3 and 4, in which the radiator body, generally designated at 1, comprises a bank of horizontally arranged radiator tubes 8 interposed between a pair of opposite righthand and lefthand end plates 2, although the drawing is showing the leftside one for clarity's sake. A header tank 3 is welded to each of the end plates 2 at a rim part 4 on both sides of the tube assembly 8.
A filling pipe 5 is inserted into a pipe hole 6, generally bored by a burring reamer, in the top wall 3a of the header tank 3 to fill the header tanks 3 of the radiator 1. The header tank 3 has its bottom wall 3b with a pipe hole 16, generally bored by a burring reamer, into which a water passage pipe 15 is inserted, disposed integrally with the filling pipe 5. The radiator tubes 8 are rigidly supported in the end plates 2, to which they may generally be jointed by welding, and each affixed to the side of the header tank 3 where they are opened into the header tank inside through apertures formed in the header tank side.
The filling pipe 5 has at a lower end thereof an opening 9 to communicate with the header tank inside through the pipe hole 6, and at its opposite end a filling hole 10 closed by a removable cap 11. Also, the water passage pipe 15 has at an upper end thereof an opening to drain the header tank 3 to recirculate the water, now cooled through the radiator tubes 8, through the pipe hole 16 to the cooling jacket via a rubber hose, not shown, connected to the lower end of the water passage pipe.
The radiator 1 receives the heated water from the cooling jacket of the engine through an inlet pipe, not shown, connected to the rightside header tank, not shown.
However, those conventional radiators have been found to have various problems due to their designs that the filling pipe 5 has its lower end portion 12 inserted into the inside of the header tank 3 such that welding provides for development of enough fillet F1 and F2 to insure water proof and pressure tight joint between the pipe hole 6 and filling pipe 5.
Thus, huge amounts of air have been tended to be entrained within the header tanks 3 during operation, just above the horizontal level A in FIG. 3 defined by the bottom edge of the lower filling pipe end portion 12. In operation, as the heated water flows from the radiator tubes 8 in the direction indicated by the arrow B, such entrained air is induced into the water inside the piping. As a result, performance can deteriorated, accompanied with abnormal noise and vibration in the cooling system. In extreme cases, corrosion can result inside the radiators and pipes.
Furthermore, in the prior art, the water passage pipe 15 have their upper end portion 13 inserted into the header tank 3 to provide for adequate formation of fillet F3 by welding enough to insure solid joint between the water passage pipe 15 and pipe hole 16, as in the case of filling pipes 5. Because of this design, greater difficulty has been encountered to drain a radiator 1 as when the engine is disassembled or the radiator is transported or stored for long periods, since some considerable amount of water has tended to be left undrained below the horizontal level C defined by the top edge of the upper pipe end portion 13. Such residual water tended to enter the engine interior, when the radiator 1 was disassembled. In some instances, it spilled unexpectedly smearing the operator's clothing. In addition, such residual water can corrode a radiator's header tanks 3 or radiator tubes 8 during storage.